Accuracy and Computational Efficiency of Finite Element Models for Low Velocity Impact on Composite Structures Subject to Progressive Damage and Delamination1

Abstract

There has been growing interest to use composites in load carrying structures where high strength and light weight are of major concern, e.g., oil industry (offshore structures and platforms, pipe systems, and tubings), sports equipment, automobiles, and aircraft industries. Despite extensive research in the last two decades, mechanical behavior of composite structures subject to contact and impact loading is still not well understood. It is well known that composites are highly vulnerable to various modes of failure and damage due to impact by foreign objects. Such impact events are not only dependent on the material behavior but also on the dynamics of the structure. Finite element (FE) packages are capable of simulating impact response of composite structures subject to impact. It requires extensive training and indepth knowledge to obtain an adequate FE model with proper impact response prediction and acceptable computational efficiency. Limited FE models have the ability to capture composite damage due to impact when internal delamination or fiber/matrix failures are present. Severe nonlinearities are encountered during FE analysis to capture composite damage progression or material degradation. This work investigates different FE modeling approaches by analyzing their prediction of force–time history and force–indentation curve occurring in composite plates as a result of low velocity impact. The objective is to provide guidelines on selecting the most appropriate approach for a given impact situation. Moreover, a computationally efficient approach in contact modeling is presented. The proposed approach yields better computation efficiency for contact modeling on both isotropic and composite materials.